stehlik



Oct. 16, 1928.

R. F. STEHLIK TELEPHONE SYSTEM Original Filed May 11, 1925 4 sheetsheet 1 mn w www ESM TEm SNT. .mm 1mm RTm wel \m%\ wi n Oct. I6, '1928.

Eudnzfh F 5mm Oct. 16, 1928. LGSSM R. F. STEHLIK TELEPHONE SYSTEM Original Filed May l1, 1925 4 Sheets-Sheet 4 HIT.'

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Patented @et 16, l928.

NETE STATES attain' earner crains.v

RUDOLPH E. STEHLK, CHICAGO, l-LLNOIS, ASSEGNR, BY MESNE ASSIGNMENTS,

TO AUTOMATC ELEGTRC NC., OF GHICAGQILLNOIS, A COREORA'IION OF DELA- WARE.

TELEPHONE SYSTEM.

Application filed May 1v1, 1925, Serial No. 29,373. Renewed May 18, 19228.

The presentinvention relates in general to telephone systems, but is concerned more particularly with telephone systems of the type in which so-called finder switches, that is, backward hunting switches, are employed to connect aY calling line with an idle trunk line; and a special object of the invention is the production of a new and improved .sending arrangement to be used in connectionwith finder systems of the directive-finder type whereby there is no loss of time between the two directing digits transmitted to a finder and between the second of the digits and the switching-through operation. Y

rl`he above result is secured, preferably by a separate sending switch for each digit and y by arranging the circuits so that the sequence switch which controls the transmission of the digits to the finders, and the switchingthrough operation so that the magnet of the sequenceV switch is energized in parallel with the magnet of the sending switch during the transmission of the last impulse of each series to the finder being operated.

Jaccording to another feature, a vertical marking wiper is provided on the first sender to mark the level to which the finder is raised and to render the sec-ond sender controllable from lines in that level only so as to prevent possible. calling lines in the other levels from interfering with the operation of the second sender to stop the finder on the wrong set of contacts.

According to a further feature of the case,Y

ployed whereby the length of the impulses transmitted to the various finder magnet-s is automatically varied to suit the particular magnet being. operated. More specifically, the termination of each impulse is under the control of the magnet to which the impulse is sent.

According to another feature of the case. arrangements are provided such that in case the magnet being operated is unable to terminate the impulses, due, for example, to dirty contacts, a timing arrangement associated with the sending apparatus, but not normally effective due to the speed at which the impulses are terminated, becomes effective to terminate the impulses and to operate the magnet in the usual manner, although at a slower rate than if itwere able to exercise the intended control over the sending operation.

A further feature of the case relates to the provision whereby the secondary switch which is used to connect a finder with a first selector is rendered preselecting as soon as the finder is allotted. lt is a special feature of the case', however, that the preselected trunk` Referring now to the accompanying drawv ings comprising Figs. l-l,.they can be un-' derstood best when Fig. 2 is placed to the right of l, with Fig. 3 under Fig. l, an d with Fig. et below Fig. 3. Vhenilaid out in this manner these drawings represent, by means of the usual circuit diagrams, asufn cient amountof apparatus in a telephone system employing the new and improved finder system to enable the invention to be understood.

Referring now to Fig. 1, this drawing shows the automatic substations A and A. The lines associated with the substations terminate in the banks of the finder F as well as in the connector banks shown at-the left. These lines are provided with the usual line and cut-ofi' relays 2 5.

The finder F, also shown in Fig. l, is controlled, when allotted by the finder allotter F A, from the sending mechanism Ishown in Figs. 3 and l to connect with any one of the 100 lines to which it has access.

The, secondary hunting switch SS, Fig. 2 is used to connect th-e finder F vwith an idle first selector, such as FS, and it is connectedA to the finder F, Fig. l, through the medium of the intermediate distributing frame IDF which is employed in order to enable the desired cross-connection between the various primary lgroups in which thc finders are located and the various secondary groups in l which the secondary switches are located to be control the operations of the finder allotter FA Fig. 11 switch S associated' with the'r'elay 201 which is used to close a circuit for the relay 201 when it is desired to energize this relay to disconnect the controlling4 relays 221-229, from the finder allotter iA Fig. 1, and to connect it instead to the spare allotter (not shown). This operation is performed, it will be understood, in case an attendant? wishes to test or adjust the finder allotter FA. In this way the ser-vice. is not interrupted at such times.- v

Fig.- 4 s-howst-he vertical sender VS' which is usedl to control? theiinders in their vertical operation;` its shows the rotary sender RS which is used to control the finders in their rotary operation; andv it shows also the sequence switchv SE whichis employed for the purpose of controlling the sequence or opera tions or the two senders VS and RS, andv to effect the switching-through operation at the end of the operation of the rotary sender RS.

Regarding the mechanical construction of the' equipment shown, it may bey pointed out that the finder F and the iirstselector" FS are f both of the well known vertical and rotary type of switch, havingbank contacts arranged in horizontal rows or levers. The :tinder F, however, is modified in that its wipers, in-y stead of standing one step below the iirstlevel of the bank contacts Vasin the ordinary case,

stand opposite the first level of the' bank con-- tacts so that in case the wipers are to he brought into engagement with a set of conta'cts in the first level they need not be first raised but are rotated right away. It will be noted that the lever 57 which controls the oi' ynormal springsA 5t), etc., is slanted at the end soth'at incase the arm 58, of which anjend view onl'y is shown, moves to the left when the wipers are rotated into engagement with contacts in the iirst level the lever 57 is permitted to rise as is also theca's'e when the lever 58 is iirst moved vertically. An arrangement of this nature is shown more in detail in my co-p'ending application filed May 19, 1924, Serial No. 714,188.

Mechan'i'cally, the finder allotter FA is, as shown, a simple rotary switch of the well knowntype in which the wipers areadvanced step by step by an associated stepping magnet and in which the wipers are advanced upon restoring stroke of the armature, rather than upon the operating stroke. The secondary switch SS, Fig. 2, the sending switches VS' and' RS, Fig. 4, and the sequence switch SE, Fig. 4,'a're all similar, mechanically, to the finder allotter FA.

Referring again to Fig. 3, the functions of each of the relays 221-229 will he pointed out Vseparately in order to facilitate a ready understanding otthev detailed' operation to be later described. v A Y Relay 221 is the iirst-level control relay.

This drawing shows also the' It is energized responsive to a call over a line terminating in the first'- level or the finders and it operates to prevent the operation of the vertical magnet or' the allotted iinder by open ing the vertical magnet circuit at armature 241, and to prevent the operation of the vertical sender VS, Fig. 4, and to operate the sequence switch SE right away by shifting the cont-rol circuit at armature 243. Y

Relay 222 is the secondary-line-switch switching relay, so called because it occupies the same position in the circuit as the switching relay of an ordinary rotary line switch. This relay pulls up when the secondary line switch' finds an idle trunk in case relay 226 is energized. f

Relays 223'and 224 are the emergency stcp' ping relay and the regular stepping relay, respectively. Relay 224 is controlled over conduct-or 7 9 to 'open the impulse circuit as soon asthe magnet to which the impulse circuit i's connected operates.

Relay 223'is slow to pull up. Its circuit is closed each time the impulse circuit is closed, but does not ordinarily have suihcient time to operate before the regular stepping relay 224 is pulled up, but, in case the contacts of thel magnet fail'to close (dueto had adjusti-nent or to dirty contacts, etc), the emergency stepping relay 223 pulls up after an interval which is slightly longer than the time required for the average magnet to operate and termi'- nates the impulse'being delivered.

Relays 225 and 226 are the auxiliary start relay and start relay, respectively.- Relay 225 is provided primarily as a circuit closing relay on account of the great number or con- Sti lou

tacts that need to be closed when the start wire isgrounded.

Relay 227 performs several functions and is called the guard relay because the upper winding of this relay is energized in a branch circuit with the magnet 77 or the iinder allotter FA, Fig. l. to maintain the start relay 228 disconnected during the hunting operation of the finder allotter, and because the lower wind-ing of the guard relay 227 is energized from armature 264 ofthe series guard-control relay 228, which remains energized during the restoration to normal of the vertical sender VS and thc rotary sender RS.

Relay 228 is the busy relay and' it energizes through resistance 230 when ground is removed from conductor 88 responsive to the condition or all finders such as F being busy or otherwise unavailable. i

The detailed description of theoperation of the apparatus shown will now be given. For this purpose it will be assumed 'irst that the subscriber at substation A, whose line is No. 25 in the iinder book, desires to malte a calland that he accordingly removes `his receiver.

`When the receiver is removed at substation the associated line for linerelay 8. Line relay 3 thereupon energizes and, in iddition` to grounding the start conductor 12 at armature 8, closes certain control circuits at armatures G and 7. rEhe control circuit closed at a mature 7 is the second-level verti al-control circuit and is used to control the finder to bring its Wipers opposite the second level ot' bank contacts. The circuit closed at armature 6 is the llo-25 rotary control circuit and is used to guide the Wipers ot the i'inder into engagement with the ii'ith set ot banl; contacts in the second level after they have been raised opposite that level.

lllhen the common start conductor 12 is grounded at armature 8 ot line relay 3, as above pointed out, a circuit is closed over conductor 12 and through armature 259 and its resting contact for start relay 226 Which is connected to battery through the switching` room supervisory relay 231. Start relay 220 accordingly energizes and closes at armature 257 a circuit tor the auxiliaryv start relay 225. At armature 255, relay 226 disconnects the combined cut-through and test c` nductor Ytroni the test conductor from the test circuit ot the `linder allotter FA, Fig. 1, and connects it instead to an open branch olE the cutthrough circuit, preparatory to the subsequent closure of the cut-through circuit; at armature 256 it places a shunt around the resting Contact and armature 200 of guard r-elay 227 for a purpose to be pointe-l out hereinafter; and at armature 258 it disconnects ground from the busy relay 229 to prevent its premature operation under' certain Conditions to be hereinafter explained; and at armature 258 and its iront contact it connects ground to the secondary switching relay 222, whereupon relay 222' energizes over a circuit which includes armature 208 and its resting.` contact, conductor 85, Wiper 7 ot' the finder allotter FA, the lirst bank contact, jumper 55, selfeinterrupting contacta 105, and the secondary stepping magnet 104. Mafmet 104, however, is not operatively engined at this time on account ot' the relatively nigh resistance oi the switching` relay 222.,1 Fig. 3. Relay 222, upon energizing. closes a second point in the cut-throiw'h circuit at armature 244, and at arn'iature 245 it opens the connection which gneviously eX- isted between, the steppingniagnet 10 the secondary switch SS and the test ivf V102 anu places ground on test wiper 102 through armature 205 and its resting contact, conductor S2, Wiper'fl ot the finder allotter FA, the lirst associated bank contact, and the `jumper 54. rThe result of this latter operation is to guard the preselected lirst selector FS. 2, from seizure.

'Returning noiv to the auxiliary start relay 225, Fig. 3, Whosecircuit is closed at armature 257 of start relay 226, the closure of' the circuitv ot this relay resulted in its energization, whereupon it closes at armature 250 a circuit through armature 206 and its resting contact, conductor S3, and Wiper 74 of the finder allotter FA for the release guard relay 5T of th-e linder F., Relay 37 now energizes and prepares at armature 4T a circuit tor the cut-through relay 3G, and at armature 48 opens a point in the circuit of release magnet 39, in addition to preparing a certain guarding circuit to be hereinafter pointed out. Ars a further result ot its energization, the auxiliary start relay 225 places a local ground on the start conductor 12 at armature 251 so as to maintain the start relay A220 energized independent ot the calling line until the common controlling` apparatus has gone through its complete sequence oi' operation. At armature 252 relay 225 places a shunt around the self-interrupting contacts 78 otl the Finder allotter stepping magnet 77 for a reason which i 7ill become ap'- parent upon a :tui-ther perusal ot the description. As a still further result ot its operation, the auxiliary start relay 225 at armature 253 disconnects the lirst-level-control the vertical magnet operating conductor 2T armature 241v and its restingl Contact, armature 203 and its resting Contact, conductor 80, Wiper 71 of the finder allotter FA, and

vertical magnet 84 to battery. Vertical mao-A net S4 is thereupon energized and it rais the Wipers 31-33 troni their normal position opposite the lirst level ot bank contacts to a position opposite the second level oit bank contacts.

In the common rcontrolling apparatus, 3, the placing ol ground upon conductor 270 by armature 254 ot the auxiliary start relay 225, also extends a Iground potential through armature 249 and its resting contact to the sender impulse distributing Wiper 312 ot the sequence switch SE. This ground potential is extended through Wiper 812 in its first position, conductor 277, armature 243 and its restino` contact, and conductor 271 to the stepping magnet 301 of the vertical sender VS. Accordingly, stepping magnet 801 energizes preparatory to advancing the Wipers 807--309 on its restoring stroke When its circuit is subsequently opened. It will be noted further that the ground potential is extended to' theterminal 321 Which is a common connecting point, it may be pointedvout, for the vertical'control conductors such as the vertical control conductor 16 oi the second level) lll) ol all the levels with the exception ol the first level. Now, since the level in which 'the calling line termina-tes is the second level, and since the Wipers normally stand opposite the lirst level, only one vertical step is required to reach the calling level. Accordingly, a circuit is novv closed from the grouni'led terminal 321 over conductor 1G, armature 7 and its working contact, conductor 17, terminal 292 Which corresponds to the second level oil bank contacts of the tinders, lirst contact in the bank ot wiper 30G and the said wiper, and the first contact in the bank oit Wiper 311i and said Wiper for stepping n'iagnet 303 ot the lequence itch SE. Accordingly, magnet 3025 energizes in mlltiple with stepping magnet 301 ol the ver( lal sender VS and in multiple with vertical magnet 3ft ot the inder F, preparatory to advancing Wipers S12-314 to their second position to terminate the vertical movement and to initiate the rotary movement as soon as the lirst impulse terminated.

As a Yfurther result et the above mentioned energination oi vertical magnet 34 of the finder F, it closes its sending contacts l0, thereby placing ground upon the stepping relayfcontrol conductor 79 which is common to the group oit tinders served by the finder allotter FA. That being the case, a circuit is closed over conductor 7S) for stepping relay 224, Fig. 3. Responsive to the closure ot this circuitstepping relay 22aL pulls up and opens at armatures 2&8 and the above traced circuit for the stepping magnets 301 and 303 of vertical sender VS and the sequence switch SE, respectively. Accordingly, magnets 301 and A303 tall back and advance their respective associated Wipers one step, and vertical magnet 3st ot the :tindcr F falls back and removes ground trom conductor T9, whereupon stepping relay 224, Fig. 3,. again falls back to transmit the next impulse. y

Since the sequence switch SE has now advanced its Wipers .3123111 trom the tirst position to the second posit-ion, no more impulses can be sent over conductor 2741. to vertical magnet 3l of the finder F, and the impulses subsequently generated. are accordingly -transn'iitted over conductor 27 and over a path to be subsequently traced to rotary magnet 3.5 of the finder F. Also, due to the fact that Wiper 314 has advanced from the l'irst contact, which is associated with the vertical control Wiper 308 ot the vertical sender VS, to its second contact, which is associated` with the rotary control wiper 311 of the rotary sender RS, the Afurther advance of the sequence switch SE to tern'iinate the second digit to be transmitted to the allotted iinder is under the control of the rotary-control' Wiper 311. Furthermore, it Will be noted that the sender impulse distributing. Wiper I 312',.being now on its second Contact, has disconnected the. sender impulse conductor 27S) from conductor 277 leading to. stepping magnet 301 oi the vertical sender by way ot armature 243 and its resting contact and conductor 271, and has connected it instead to stepping magnet 302 of the rotar sender RS.

Upon the 'falling back ot stepping relay 224-, ground Yfrom the grounded conductor 270 through the resting contact and armature 263 is again extended atarmature 24? by way ot' lconductor 280 to the .under-impulse distributing iviper 313 oi the sequence switch SE. Accordinglv a around Jotentral 1s eX 1 l 1 r. 7 n l. tended lurtner through the-second contact in the bank ot n'iper 313 tln'ough conductor 275, armature 204 and its resting contact, conductor 81, and Wiper 'T2 and its tirst contact to rotary magnet 35 otthe finder F. By the operation ot rotary magnet 35, the Wipers 31--33 are rotated into engagement with the first set of bank contacts in the second level.

ln the common sending equipment, the

falling back of stepping relay 224, Fig. 3,

Aloo

tary control Wiper 311 and through the second Contact inthe bank of Wiper 314 and the said wiper lor stepping magnet 303 of the sequence switch .SE to terminate the rotary operation utter the first impulse, but since this is not the case, the rotary control circuit closed over conductors 18 and 19 at armature 6 ot relay 3 returns over conductor 19 to the common terminal 203 whichis connected to the li'lth contact in the bank of the Arotary control Wiper 311 instead of the lirst. 1t may be pointed out further. that due to the action ot the vertical marking Wiper 309 of the vertical sender VS, the impulse lead which Wiper 309 terminates is connected to terminal 295 common to all lines in the second level to the exclusion of terminals such as 204i common to the other levels, respec-r tively. Accordingly, 1t may be seen that the Y lli cuits of rotary magnet of the iinder F and stepping magnet 302 of the rotary sender RS, respectively. Stepping magnet 302 now falls back and advances the wipers 310 and` 311 one step, whereupon wiper 311 disconnects ground from the lirst rotary control conductor and connects it instead to the second rotary control conductor. lV hen rotary magnet 35 falls back and at contacts Lll removes ground trom conductor 7 9, stepping relay 22e, 3, again falls back and at armatures 248 and 245:9 closes the circuits of magnet 35 oi the finder F and magnet 302 oi' the rotary sender RS, respectively.

rlhis alternate operation ot the magnets 35 and 302 and stepping relay 22A continues as described until tour impulses ot cu 1rent have been delivered to rotary magnet 35 of the finder F and to stepping` magnet 302 oi the rotary sender FS, and when magnet 302 falls back at the end of the fourth impulse and advances wiper 311 into engagementthe fifth Contact (in which the ii'fth rotary control conductor terminates), a circuit is prepared tor operating stepping magnet 303 of the sequence switcn SE in multiple with magnet 302 upon the next impulse. That being the case, when the circuit is next completed and current is next transmitted to wiper 312 ot' the sequence switch SE in its second position to operate magnet 302 ot the l sender RS, coincident to the transon ot the iiith impulse to the rotary 35 of the finder F, a circuit in multi- L mag iet 302 is closed through the vertical marking wiper 309, second associated bank contact, the terminal 205 common to the lines in the second level ot' the iinders,

vrotaryf-ccntrol conductor 18, working contact ot' armature 6 and said armature, conductor l0, terminal 293, common to all fifth r y step lines. litth contact in the bank ot wiper 311 and said wiper, second contact in the bank or' wiper 314.- and the said wiper and n agnet 303 to battery. Accordingly, 303

Zes preparatory to advancing the wip- 312-914 when Vit subsequently falls back. the linder F, the wipers 31-33 have at 's time been advanced to the iiith 'bank contact in the second level by the operation Y ln the common sending equipment, Fig.

en stepping relay 22% pulls up respon- 'fifth grounding of conductor 79 impulse circuit at armatures 248 'and Li-0 whereupon magnet 35 oi the finder Qnet of the linder F it again ing position to the switching-through position. The sequence switch control wiper 314, upon advancing to the third contact, encounters the grounded conductor 276, whereupon magnet 303 energizes preparatory to advancing the wipers out ot position 3 into position A. The under-impulse distributing wiper 313 engages a dead Contact in the third position. The sender-impulse distributing wiper in its tnird posit-ion connects with the cut through conductor 278 over'which the cut through operation is to be controlled subsequently.

ln the finder F, rotary magnet 35 falls back responsive to the termination of the fifth impulse and removes ground from conductor 79, whereupon stepping relay 2241-, Fig. 3 falls back and at armature 2&9 again extends ground to the sender impulse distributing wiper 312. This results in a ground potential being extended over connector 278 to the upper winding oli the combined guard and. cutthrough control relay 227. A branch of this circuit extends through armature 209 conductor 86, and contacts '78 to magnet 77 of the finder allotter FA. Magnet 77 energizes preparatory to advancing the wiper 71-76 when it subsequently falls back. Although it opens its own circuit, as traced, at contacts 78, magnet 77 does not fall back responsive thereto owing to the fact that contacts 7 8 are shunted by armature 252 audits working Y contact of relay 255 through a connection which included armature 210 and its resting contact and conductor 87.

As a result ot theabove mentioned closure ot' the circuit ot the. upper winding ot the combined guard and cut-through control relay 227 F 3, this relay pulls up and at armature 259 disconnects the start conductor from the slow acting start relay 226, at. the same time completing the cut through circuit. Start relay 226 does not tall back at this time it may be pointed out on account of the tact that it is slow acting. The cut through circuit extends trom ground on the grounded start wire l2 through armature 259 and its working contact, working contact and armature 21M, working contact and armature armature 207 and its resting contact, conductor 84, wi 3er 75 ot the nder allotter FA. the first associated bank contact, olif normal spring 50 and its upper Contact, armature t7 and its working Contact, relay 36, and resistance 38 to battery. Relay 36 energizes over the above traced circuit unless the line of substation A has become busy during the time elapsingv between the removal of the receiver and the arrivaloi:l the tinder F due to a call being extended to the line through the connector bank terminals shown at the left. Assuming the line to be still in the idle calling condition, relay 36 pulls up and extends the line conductors orp the calling` line by the way of working contacts of and armatures l2 'lit andY 46 over the heavy talking conductors shown to the first selector FS Fig. 2. Relay 36 at armature 43 also disconnects the test .wiper 32 from the junction of resistance 3S relay 3 from the line of substation A. Line relay' 3 new falls' back and separates conductors 18 and 19 and conductors 16 and 17 at armature 6 and 7, and at armature 8 removes ground trom the start conduct-or 12, leaving this conductor grounded in the common equipment at armature 251 oit the auxiliary start relay 225, Fig. il. As a 'further result ot energization of relay 36 of finder F, this relay7 locks itself to the grounded release trunlf. conductor 72 at armature 44, and at armature 415 opens a. further point in the circuit of release magnet 39.

vIn the first selector FS, Fig. 2, line relay 121 energizes responsive to the tina-l extension of the calling line at relay of iinder F, as above .pointed out, and closes at armature 131 a circuit for release relay 122. Release relay now energizes and at armature places ground on release trunk conductor 109 so as to maintain the connection between the first selector and the calling line through the finder F and the secondary switch SS independent oit the common controllingr equipment which is to be shortly associated with another finder-secondary link. As a further result of the energization of release relay 122, it opens a point in the circuit et release magnet 126 at armature 134: and closes a point in the circuit of vertical magnet 128, and at armature 132 closes a point in the circuit of the common chain relay 106 for a purpose which will be later pointed out. The first selector is now in readiness to be operated in accordance with the first digit ot' the desired number. The description ot this operation, however. will be deferred until the description et the opera-tion ot the common controlling apparatus has been completed.

As a further result ot the enorgization of relay 227, Fig. 3, it disconnects the auxiliary stepping control relay at armature 26h` as to prevent interference from this source at this time, and atar-'matures 261 and 262 it grounds conductors 272 and 273 respectively, extending to wipers 307 and 310 ot' the vertical sender VS and the rotary sender RS, F ig. 4. Vlt may be seen that the ground potential on wipers 307 andl() is extended through the self interrupting contacts 304 and 305 tothe magnets 801 and 302. Accordingly, these magnets operate in buzzer like manner with the result that switches VS and RS are returned to their normal position in the usual ina-nner. It will be noted that the ground potential for driving` magnets 301 and 302 is derived through the low wound series gu ardcontrol relay 228. Accordingly relay 228 energia/es when the restoring circuits are clos-cd and it remains energized until they are both opened on account of the 'fact that it is slow acting and is able therefore to maintain its armature attracted notwithstanding the interruption in its circuit. It may be pointed out that relay 22S at armature 26-1- closes a circuit through the lower winding of the relay 227 so as to maintain this relay energized and the restoring circuits of the switches VS and RS intact at armatures 262 until the restoring operation is completed. At armature 265, relay 228 closes a circuit through the resistance 266 and through the switch-room supervisory relay 231 so that an attendant may be informed in case the restmfing circuits are not opened within a reasonable length of time.

After the interval for which it is adjusted the slow acting start relay 226 falls back in response to being disconnected at the resting contact and armature 259. At armature 255 relay 226 disconnects the combined cuttlhrough and test conductor (new grounded at the rst selector FS) from the cut-through circuit and connects it back to the test circuit again; it opens the circuit ot lthe secondary switching relay 222 at armature 25S, and again .closes a point in the circuit of busy relay 229, whereupon the relay 222 'falls back, but without any particular result at this time; and at armature 257 it opens the circuit or' the auxiliary start relay 225. lWhen this occurs relay 225 tails back and removes the local ground from the start conductor l2 at arniature 251; reconnects conductor 221 to the terminal 26S) atarmature 253; and at armature removes ground from wiper 312 of the sequence switch .SE and consequently troni cmiductor 278 extending to the upper winding` oi the guard relay 227 and through armature 200 and its rest-ing contact ad c luctor S6 to stepping magnet 7" u ot the linder allotterv FA. The upper winding ot rcla=.fV

227, however, remains grounded this time Yfrom theV cut-through and test conductor Sil (which picks up `ground through wiper 7 5, spring 50 and its upper contact, armature 41:7 and its workin contact, and the working contact and arie rature 4A, 'from release trunk conductor 72) through the resting contact and armature 207, ar1natlure'25 and its resting lcontact and the resting contact and armature 267. Stepping magnet 77 of the finder allotter FA, however, nowA falls back because the shunt is removed troni around its contact 78 at armature 252 oit rel-ay 225. Vhen stepping magnet 77 of the finder allotter FA tails baci: it advances the wipers 'le-76 one step. In case the finden associated with the second set of benl-i contacts oit the finder allotter FA busy wiper 75 engages a grounded bank contact with the result that the :ircuit over conductor Se, lfor the upper winding ot th' Vhereinbetore pointed out) Vtails bacl; ai

vances the Wipers B12-314 from the thiVl Y cordance with the first digit kcloses a locking circuit for itsel relay is maintained closed 'from the i potential encountered by Wiper 75. inis .ground potential is extended through the previously traced circuit to stepping inap through ontact 7S. Accordingly the sel terrupted magnet 7T advances the 71-76 of the allott-er Fili to an il le At armature 260, relay 22T main Luns cond :y tors 273 and 2T4disconnected so as to avoid interleence With the busy iinders, and armature 259 it maintains start relay 226 disconnected so as to prevent a premature operation ofthis relay.

Y YVhenan idle finder is reached, the finder allotter FA ceases Vto advance and the guard relay 22T falls back and again connects up start relay 226 at armaturev 259. Also,

sponsive to the finding ot t i' stepping magnet Fig. Ll, Wl -i position is maintained energized with the upper Winding of guard rel y 22 lThe fourth set of contacts are multipled with the lirst set of contacts, the titth set is rnultipled ot contacts to the 'fourth set of contact-s.

with the second set, etc. Accordingly, the sequence switch E as well as the remainingg,l part ol the common equipment is ready to be used in handling anothercall.

The operation of the lirst selector FS Will nouT be taken up. l,When the subscriber at substation A turns his calling,l device in acthe desired number, line relay 121 falls bach a number ottimes corresponding to the number et iinpulses produced at the calling substation. Each time it falls back it closes at armature 131 a circuit through arniature 13eL and its front contact, series relay 128, and vertical magnet 128 to battery, By the operation of vertical magnet 128, trie wipers lasik-145 are raised stepby step until they come to rest opposite the desired level ot barili: contacts. Relay 123 is energized in series vvith vertical magnet 12S and, being slonv acting, maintains its armature attracted throughout the series ot impulses. llt armature 135, relay 123 prepares a circuit liorstepp'lng relay 121,'ivhicli is completed oil normal contacts i upon the first upward step ot the .yitch, and which includes, in addition, the interrupter 152 of the rotary magnet 12"?. Relay 121 energizes When this circuit is clesedanc it tat armature 13G, and at armature 13?' prepares a circuit lor rotary magnet 127.

it the end ot the vertical movement, the slovv acting relay 123 falls back and at arniature 185 completes through armature 13.7 and its Working' contact the circuit ot rotary magnet 127. Rotary magnet 127 new pulls up and advances the Wipers MfS-1&5 into engagement with the first set of bank contacts again antL advances the Wiper another sten.

yor line relay 121 at thercupon'talls back and opens a turtle point in its own circuit at armature 13G, at v the saine time opening the circuit of rotary magnet 12? at armature 13T. Rotary magy net- 127 nov.'v falls baclr also and closes its ontacts 152 again.

From this point, the operation depends upon Whether or not the trunl; terminating in the first setot` banl; contacts is busy or idle. T `t is idle, relay 125 now pulls up, seizing the trunk.

Assuming on the other hand that this tr u nl; isbusy, relay 125 is short circuited by the ground potential encountered on the busy test contac" by test Wiper 111eL and it does not energine. Relay 1241 energizes trom this same ground potential and again closes at armature 187 the circuit ot rotary magnet 12?'. vVhen this occurs rotary magnet 127 pulls up rfhis alternate operation ot relay 12-l ant magnet 127 continues as described until an idle trunk is reached, which trunli, it will be assumed, is the one comprising conductors 1019-151 and terminating` in bank contacts 145-1118. Talp/ hen this idle trunk is reached, switchingrelay 125, being no longer short circuited, energizes in series With relay 124; i/roni the grounded release trunk conductor 109. Relay 1241 is not operatively energized at this time on account el' the relatively high resistance of relay 125. Upon energizing, relay 125 removes ground from armature ariiiature 141, tlierel" f opening the circuit ot' the slouv acting relay 122; it closes a niultiipile point in the chain circuit at armature 139; it opens the testcircuit and prepares the holding circuit at armalture 1110; and at armatures 138 and 1&2 it

disconnects conductors 108 and 110 from line relay 121 and extends them by Way ot wipers 1418 and 1el5,'banl contacts and 11C, and conductors 1l9and 151 tothe line relay of the ksivitcli to which the seized trunli extends. Accordingly, the line and ic ease relays (not shown) of t e seized trunk pull up, and the latter grounds the release trunk conductor 150, thereby completing` the usual holding` circuit betore the sloiv acting release relay 122l ot the iii-st selector FS has had time to fall back.

Tl e remainingl part of the establishing ol" the connection takesV )lace in the usual inanner. f

1t Will be noted that the chain circuit is kept closed at the first selector FS subsequent to the falling baclr of relay 122 at armature 13?/ of relay 125.

At the end ol the conversation the subscriber at substation A replaces his receiver, whereupon theground is removed in the usual manner from release trunk conductor 150 ot lthe trunk seized by the first selector FS,

whereupon relay 125 of the first selector l" and relay 36 o1" the linder F both fall back.

In the selector FS, the decnergization oiE relay 125 results in the closure ot the circuit at release magnet 126 through armatures 141, 131, and 134, and through the oil normal contacts 129. Release magnet 126 thereupon energizes with the result that the wipers 143-145 are restored to normal position in the usual manner. The circuits of magnet 125 is opened at oil normal contacts 129.

In the linder F, relay 3G, upon falling back, removes ground ii'rom wiper 32, whereupon cutoil relay 2 falls back and again connects up ground to one line conductor and line relay 3 to the other. Relay 36 also completes the circuit ot release magnet 39 at armature 45. The circuit includes armature 48 and its resting contact, arn'iature 45 and its resting Contact, and oif normal spring 51 at itsupper contact. Release magnet 39 now'encrgizes with the result that wipers 3,133 are restored to normal position in the usual manner, whereupon the circuit of release magnet 39 is opened at off normal spring 51.

rlie entire connection is now released and the apparatus involved therein lis ready for use in establishing other connections.

Considering now a call from the subscriber at substation A', whose line terminates in the bank contact set No. in the bank of the iinder F, Fig. 1, when the subscriber at substation A removes his receiver, a circuit is closed :t'or line relay 5. Relay 5 thereupon energizes and at armature 11 places ground upon the common start conductor 12 5 at armature 19 it closes the No. 15 rotary control circuit over conductors 14 and 15; and at armature 10 it places ground on the .tirst level control conductor 13, thereby closing a circuit through terminal 209 common to the lines of the first level, normally closed contacts controlled by armature 221, and the resting con- )tact and armature 253 for the tirst level control relay 221. Relay 221 is able to energize, it may be pointed out, before the start relay 226l and the auxiliary start relay 225 have both had time to pull up after the start wire is grounded. Upon energizing, relay 221 closes a locking Acircuit for itself and opens its initial circuit at armature 242; opens a point in the vertical magnet operating circuit at armature 241 so as to prevent the usual magnet circuit from being closed at this time as the wipers are already opposite the first level of bank contacts; and at armature 243 it opens the circuit for advancing the vertical sender VS and prepares over conductor 281 a circuit for automatically advancing the sequence switch SE, Fig. 4, from its first position to its second position.

'Accordingly when the auxiliary start relay 225 pulls up following the closure of its circuit at armature 257 lof start relay 226, it

closes the usual circuits at its armatures ductors 279 and 280 to the sender-impulse and the linder-impulse distributing wipers Y 312 and 313. The ground potential placed on wiper 313 is extended through conductor 277, armature 243 and its working contact, conductor 281', and the self-interrupting contacts G tothe stepping magnet 303 of the sequence switch SE. Accordingly, magnet 303 operates and opens its own circuit, whereupon the wipers 313-314 are advanced one step from the vertical sending position to the rotary sending position.

The ground potentialvon wipers'312 and 313 is now extended in the usualmanner to the rotary magnet of the finder F and to magnet 302 of the rotary sender RS in the manner hereinbefore described, and stepping relay 224 is controlled over the common stepping' conductor 79 to interrupt the circuits at armatures 248 and 249 in the hereinbefore described manner, thereby advancing the rotary sender RS and the linder F simultaneously. v Y Y At the end of the fourth stepzof the finder F and ot' the rotary sender RS, the wiper 311 oi" the rotary sender RS is standing' on the li'lth 'associated bank contact. Accordingly, when the im ulse circuit is again closed, upon the falling Eack of the stepping relay 224, a circuit in multiple with magnet 302 is closed through the vertical marking wiper 309 of the vertical sender VS in its first position, terminal 294, conductor 14, working contact and armature 9 of line relay 5, conductor 15, terminal 293, fifth contact in the bank of the rotary control wiper 311 and said wiper, second contact in the bank of wiper 314 and said wiper, and stepping magnet 303 oi the sequence switch SE to battery. Accordingly', magnet 303 is energized in multiple with the rotary magnet of the finder F. As soon as the impulse is terminated, upon the pulling up of stepping relay 224, Fig. 3, the sequence switch SE advances from its second position to its third position with the hereinbefore described results. From this point on the operation is the same as described hereinbefore and need not be repeated.

Certain points in connection with the circuits sliown. which are not conveniently described in the course of a call will now be pointed out a little more in detail. Considering first the arrangement whereby the secondary switch SS, Fig. 1, is made preselecting, it will be noted that, with the finder allotter FA, Fig. 1, standing on the finder and with the remaining part of the equipmentY in the normal position shown, the test wip r 102 of the secondary switch SS is connected to the stepping magnet 104 through the IDF jumper 54, release trunk conductor 7 2 of the lio , relay 227, armature 28 and its resting contact, conductor 85, wiper 76 and the first associated bank contact, IDF jumper 55, and the self-interrupting contacts 105. Accordingly, the magnet 104 is operated in the usual manner to advance the switch to an idle trunk if it is not already on one. Furthermore, it will be noted that there is normally no circuit for pulling up the secondary switching relay 222, 3. Accordingly,

. when the secondary switch SS reaches an idle trunk when there is no calling line to be found by the allotted finder. the idle trunk is not made busy. This trunk is left idle because, considering a particular secondary group, the various secondary switches in this group are associated with finder switches in different hundred-line groups. Accordingly, if there are only a few idle trunks in the group, it is best not toy actually make a trunk busy to the exclusion of use by other secondary switches until a call comes in. lIhe switching relay circuit remains open at arma ture 258 and its working Contact of start relay 226 until the said start relay pulls up Start relay 226 also, it will be noted, shunts the resting contact and armature 260 at armature 256 so as to maintain the connection between the test wiper 102 and the stepping magnet 104, 2, independent of the restingl contact and armature 260 of the guard relay227.

A certain point now in connection with the rendering of the finders, such as F, busy to the finder allotter FA will now be considered. It will be noted that the release-guard conductor 83 is extended through the wiper 74 and its first associated Contact to the release guard relay 37 of the finder F. Accordingly, when the release guard conductor 83 is grounded vat armature 250 of the auxiliary start relay 225, as hereinbefore pointed out, the release guard relay 37 pulls up and remains up as long as the auxiliary start relay remains energized. It will he noted that the cut-through conductor 84 is extended through the cut-through wiper to olf normal spring 50 and that as soon as the release-guard re-y lay 37 pulls up a ground potential is placed at armature 48 on. off normal spring 50 through the lower contacts thereof, thereby extending a ground potential down to the cut-through wiper 7 5 which is used also as a test wiper. rIhis does not have any particular utility at this time, however, on account of the fact that the cut-through wiper is disconnected from the test branch at armature 255 of start relay 226 at this time. However,

when the release-guard relay 37 is pulled upV through the IDF jumper 53 and through the olf normal contacts 49 of the finder F, responsive to the energization of the chain relay 107, Fig. 2, when all the first selectors such as FS are busy, the ground potential placed through armature 48 and its working contact, and the resting Contact and spring` 50 on the first contact in the bank of wiper 75 is effective in advancing the finder allotter FA to the next set of bank contacts, provided the common controlling mechanism is in the normal position shown, or is in the position of testing for an idle finder immediately after the -completion of the call.

It may be pointed out further that the finder F is maintained busy to the finder allotter FA subsequent to the falling back of the release-guard relay 37 as soon as the common controlling apparatus is through setting the finder F, not from the release trunk conductor 72, but from the local ground through the resting contact and armature 47, and through the upper contact and off normal spring` 50. Accordingly, this ground potential is available for guarding the finder F until the olf normal springs shift back to their iormal position shown in the drawings when the finder is finally released.

lRegarding the auxiliary stepping` relay 223, Fi 3, this relay is slow to pull up and it does ,not therefore have time to pull up in the ordiand armature 263, and armature 247 and itsA resting contact for the auxiliary stepping relay 223, is effective in energizing this relay in a kperiod of time somewhat longer than ordinarily required for energizing the operating magnet of the finder. Upon energizing, relay 223 closes at armature 246l a local circuit for 'stepping relay 224, whereupon relay 224 energizes to open the impulsing circuit at armatures 248 and 249 and to open the circuit of the auxiliary stepping relay 223 at armature 247. Relay 223 now falls back fairly quickly, notwithstanding the copper slug on the armature end of its core. owino; to its stiff adjustment, and at armature 246 opens the circuit of stepping relay 224 which thereupon falls back to send the next impulse.

Referring now to the sequence switch SE, Fig. 4, it will be noted that the circuits closed during the second three positions of the se- .quence switch are the same as the circuits closed during the first three positions of the switch, respectively. The same, it will be noted, is true of positions seven, eight and nine. In positions ten and eleven, however, wipers 313 and 314 both encounter dead contacts and wiper 312 is connected with contacts wired to the vstepping magnet 303 through the self-interrupting contacts 306.

Qluralit f ot operatino' Accordingly, when the sequence switch SE advances to position ten at the end of the call which occupies positions seven, eight and nine of the sequence switch SE, a circuit is prepared for magnet 303 which is closed over conductor 279 upon the next energization of the auxiliary start relay 225. lVhen this circuit is closed the magnet 303 advances the wipers S12-8H through positions ten and eleven andr into position one again, whereupon the allotted finder is started into o peration in the usual manner.

Regarding the busy relay 229, Fig. 8, this relav is normally included in the circuit from ground through armature 258 and its resting contact, relay a Ad resistance 28() to butg tery. However, the normally grounded conductor 88, which is `commtm to all the af'- sociated 'inders, is connected at ne junction of relay 229 and resistance 239. Conductor 88, it will be noted, is grounded in the linder F through armature i8 and its resting contact, armature l5 and its resting contact, and oil normal spring 5l and its lower contact. lVhen the finder F is in use, however, this ground potential is removed from conductor 88, lirst at armature 48 and subsequently at oil normal spring 5l. lVhen all linders are in use, the ground is completely removed from conductor 88, whereupon busy' relay 229 pulls up and prevents the operation of the finder allotter FA at armature 287 which is separated from its resting Contact. Also, busy relay 229 closes at armature 268 a circuit through the lower winding et relay 227, which. thereupon pulls up and disconnects start relay .226, etc, rIhe reason for taking the cuit of relay 229 through armature 228 and its resting contactis to prevent the premature operation of busy relay 229 when the call comes in that is to take the last available linder.

What is claimed is:

l1. In a telephone system, a two-motion finder switch, a calling` line terminatino in the banlrthereof, prim ary and secondary m. nets for driving said finder in its respective movements, means toi' sendino a s.' idle train of impulses to said finder, and means independent ci control by said impulses for diverting the first part oit said series to said primary magnet and for diverting the remaining part tosaid secondary magnet, whereby said finder is set upon the bank contacts ot' the callingl line. i

2. In an electrica controlling system, a

ig magnets, means for generating a single series of similar impulses each sin'iilarly spaced from the others, and

synchronously operated counting controlled mechanism ltor distributingl said impulses amongst said magnets in any one oilE several predetermined combinations. l

3. In electrical controlling system, two

pulses t'rom traversing said path.

5. In an electrical controlling system, an impulse generator', a path for the impulses generated thereby, and means comprising a step-hy-step switch operated by only one or' the impulses transmitted over said path for barring further impulses from passing over said path.

6, In a directive finder switch system in which the linder switches are of the two-motion type, a finder controlling arrangement comprising an impulse generator, a primary motion counting switch having progressively movable wipers, a secondary motion counting' switch having progressively movable wipers, and a counting-switch-control sequence switch having progressively movable wipers.

7. In a vertical and rotary finder switch system for use in telephone systems in which common sending mechanism is used to set the finders on calling lines, a register associated with the sendingmechanism for registering the extent of the primary operation of an operated .linder to place the further operation of the sending apparatus under the exclusive control of calling lines in the group selected by the primary operation of the finder.

8. In an electrical controlling system, an impulse generator for generating two series of impulses, two counting switches for counting said series, respectively, connections con-V operating magnets of the finders, an allotter n for connecting said Contact to an idle finder, and means controlled by the operating magnets of the allotted finder for controllingY said relay to operate said Contact.

10. In a step-by-step finder switch system for use in telephone systems, a relay having` a Contact for transmitting impulses to the operating magnets of the iinders, an allotter for connecting said contact to an idle finder. means controlled by the operating` magnets of the allotted finder for controlling said re- 1,688,161 ll il lay to operate said contact, and timing means for exercising control over said relay in case the magnets or" the finder are unable to do so.

ll. ln a telephone system employing finder switches, numerical switches, a secondary line switch connected to each finder switch, means for allotting an idle finder switch for use before a call is received, and means for thereupon causing the secondary switch connected with the allotted finder to select an idle numerical switch.

l2. ln a telephone system employing finder switches, numerical switches, a secondary line switch connected to each finder switch, means for allotting an idle finder switch for use betore a call is received, means for thereupon causing the secondary switch connected with the allotted inder to select an idle numerical switch, and means responsive to a call for rendering the selected numerical switch busy to other econdary switches.

13. ln an electrical controlling system, an impulse generator tor generating a series oi evenly spaced impulses, a counting switch having wipers and a magnet, said magnet being energized by said impulses to advance said wipers to count said impulses, contacts engaged by said wipers, means for marking a certain one of said contacts to deline a group of said impulses, a plurality of paths for said impulses, i cans controlled through said n'iarked contact and counting switch wiper which engages it, ior ending said group by diverting the remaining impulses of the Eeries to another or" said paths.

The method ot preventing number scrambling, oit simultaneous calls received by a control mechanism, by registering the level designations of the calling lines in a level selecting control, by preparing circuits for registering the contact designations of the lines in a contact selecting control, and by closing said circuit after said level selecting control has been positioned, to register the contact designations of only those calling lines which are in the selected level. y

15. ln a telephone system, a group of inder switches having banks, a plurality of groups of lines terminating in said banks each oi' said groups comprising a level in said banks, a. common control mechanism comprising a. senderptor delivering impulses to said finders, a plurality ot counting switches and a sequence switch, means individually associated with each of said lines and responsive to a call thereon to start said control equipment functioning, to mark the level containing the line in one of said counting switches and to prepare a. loop for marking the line in another or said counting switches, means responsive to the starting of said co-ntrol equipment to position said one counting switch on said marked contact and to position one or said linders on the level corresponding thereto, and means for then closing a circuit through said sequence switch, said first. counting switch and said loop to said other counting switch to register said line designation therein preparatory to positioning said iinder thereon. f

i6. ln telephone system, a pluraiity o" lines arranged in level groups, finder switches having access thereto, control devices for said finders comprising primary and secondary motion controls, marking deviies individualV to each line, means responsive to simultaneous calls on lines et' different levels for operating the respecti e 7' devices to register' the level designations or'Lid lines in said primary motion control and prepare a point in the line designation circuit@` of said lines, means in said control eevice operator in response to the operation oi said marking devices to select a certain dfsignated level, and means complete said prepared re`r icuits et tie lines in said selected level, to register those lines in the secondary motion control preparatory to governing that control. 17. ln plurality or contact 'for closing ated by said magnet lirst relay to open said m.4 means cont-rolled by said a definite interval, to opent it said magnet contacts t i8. In a telephone sys indcr switches each havin nagnets, a common contro allotter for associating sail c r ment with said one or" said finders, a st relay in said control equipment tacts Vthrough which circuit is c s said iinder magnets in order, a revertive pulse conductor extending from said stepping relay to said finders independently or" said allotter, and means operated by said magnets to operate said stepping relay over lsaid conductor to open `said magnet circuit.

19. The method of controlling the spe at which impulses are generated by an lll) gi, lil

lill

1mpulsing device, which consists ot closing circuit to the magnet which is to be impulsed and of closing a pulse terminating circuit b contacts closed by that magnet when it i in its fully operated position.

20. in a telephone svstem, a plurality of lines terminating in a switch bank having levels, a rnder switch having wipers which normally stand ogposite one ot said levels, a shaft supporting said wipers, control means 'tor operating said lindcr step-by-step no sition said wipers upon one said line teri inals either in the level opposite which se wipers are standing or in any other level, contacts on said linder switch. and shaft controlled means for operating said contacts Ui rd t.

during the first step operation irrespective o1 the direction trie shaft is moved b v that step.

2l. In a telephone system, a @groep ot lir a group of finder switches having' aceethereto, secondary switches coiuected to sait finder switches, a group oi numerical switches accessible to said secondkt ,ry switches7 a control eqnii'nnent common to said iinder switches, an allotter l'or a i-iociating said c" trol equipment with one oi said finde; switches7 start relay in said control equipment energized in ,spense to a call on one et said lines to start said equi ifnent 'tanctioning to position the allettet ,Finder on that line and te establish a connection therewith, means associated. With said line and responsive to the establishment of said connection to deenerpgize said start relajvj means responsive to that deencrgization ot said start relay for operatA j said allotter to connect another finder With said control and to operate the secondary switch associated sith said an other finder to selecta numerical switch and Q3. In a telephone system; a plurality oi` lines terminating in a switch bank having' levels, a linder switch having' wipers which normally stand opposite one oit vsaid levels, a nimary magnet for moving; said Wipers to select one of said levels, a secondary magnet 'for moving' said Wipers to select a. line in a normally stand opposite one of said levels, a

primary magnet for mo iing said Wipers to select one ot 'd levels, a secondary magnet for moving said Wipers to select a line in a selected leveh control means responsive to the initiation of a call on one oi said line for operating); said magnets in turn, to position said Wipers on. the contacts of said line1 and a rela;7 energized in response to the initiation ot a call in the level opposite which said Wipers normali)7 rest for removing said primary magnets from said control means and operating said secondary magnets to position said Wipers on the contacts of Asaid calling; line.

In Witness whereof, I hereunto subscribe my name this 9th dav of Mav, A. D. 1925.

' RUDOLPH F. STEHLIK. 

